fix: add completion mode object check (#3515)

api/core/model_runtime/model_providers/openai_api_compatible/llm/llm.py

@@ -152,6 +152,9 @@ class OAIAPICompatLargeLanguageModel(_CommonOAI_API_Compat, LargeLanguageModel):
 
             if (completion_type is LLMMode.CHAT and json_result['object'] == ''):
                 json_result['object'] = 'chat.completion'
+            elif (completion_type is LLMMode.COMPLETION and json_result['object'] == ''):
+                json_result['object'] = 'text_completion'
+                
             if (completion_type is LLMMode.CHAT
                     and ('object' not in json_result or json_result['object'] != 'chat.completion')):
                 raise CredentialsValidateFailedError(